Since it is a target pistol and target shooters have the habit, unknown to a lot of Internet Shooters, of cleaning their guns, S&W just did not think it necessary to go to the trouble of making a M41 out of low machinability stainless. I guess their current clientele made it worthwhile to change the 952 to stainless, but it was at a huge increase in price.
If you want a white M41, a dealer here had some that were satin nickel plated on special order for some large distributor. That was several years ago, and there were not many, so finding one would be hard and the novelty price would be high.